A pulverizer that pulverizes a solid fuel such as coal into a fine powder smaller than a predetermined particle size has been known (refer to Patent Document 1, for example).
Patent Document 1 discloses a method for detecting rapid combustion and stopping a pulverizer when rapid combustion similar to dust explosion occurs inside the pulverizer. Specifically, Patent Document 1 discloses a method for detecting a pressure differential by subtracting the pressure of an upper internal portion inside a housing of the pulverizer from the pressure inside a hot air duct that supplies hot air to the pulverizer interior, and stopping the pulverizer when this pressure differential is negative.